After bowling Wellington out for 318 before lunch on the final day, the Volts were chasing 214 to win at Karori Park.
Just as in the first innings, Jesse Ryder and Derek de Boorder stood up for the Volts.
Ryder scored an unbeaten 65 to go with his 108 in the first innings, while de Boorder added 58 not out to his 146 in Otago's first innings.
Otago collected 19 competition points - including four bowling and three batting bonus points - and is now fourth, on 47 points, just two points behind the second-placed Northern Knights.
Canterbury also has 47 points and is in third place.
Volts coach Dimitri Mascarenhas heaped praise on Ryder and de Boorder after the match.
''Since Jesse has come back from injury, he has been brilliant,'' he said.
''He showed his class in the first innings on a tough wicket. Wickets were falling around him but he got stuck in and once he got to 50 he made it count.
''Derek has been really short of runs, so just a huge credit to his work ethic. It's great to see all his hard work pay off with a brilliant hundred to set the game up, and 50-odd not out at a run a ball to finish off.''
Mascarenhas also saved some praise for his bowlers, saying they ''won it for us'' in the first innings.
After captain Aaron Redmond won the toss and elected to field on day one, Otago rolled Wellington for 272.
Otago built a 105-run lead after its first bat, before Wellington got through to the end of day three at 270 for seven.
Resuming yesterday morning, Jeetan Patel and Andy McKay were dismissed with just 10 more runs added to the total.
However, No 11 Brent Arnel dug in for over an hour for his seven runs, as he and James Franklin (139) added 38 valuable runs for the last wicket. Neil Wagner was the pick of the bowlers, finishing with four wickets for 90 runs from his 26 overs.
Jacob Duffy picked up three for 92 from 26 overs, while Craig Smith (two wickets) and Mark Craig (one) also chipped in.
The match ended a day later than originally scheduled, after the first day was moved back because the ground was deemed unfit to host first-class cricket.
The bowlers' run-ups were particularly of concern, and New Zealand Cricket is deciding whether Karori Park will host Wellington's next home game.
Mascarenhas said it was ''unfortunate'' the ground was not ready on Sunday, but said there were no problems once the match started.
The Volts flew back to Dunedin last night and will spend the next week in the city, before playing Wellington in Queenstown next Saturday.
In yesterday's other match, Auckland thrashed Canterbury by 10 wickets in Rangiora.
After rolling the home side for 266 in its second innings, Auckland needed only eight overs to score the 44 runs needed to win. Auckland tops the standings on 61 points.
